The purpose of this project is to develop a portable, multi-site, low cost, fast and facile device for quantitative assessment of bone quality that is suitable for mass screening and early identification of osteoporosis risk group. The device will measure ultrasound velocity and frequency- dependent attenuation in several skeleton sites by a number of electronically switched ultrasonic probes. The probes are intended for surface and through transmission sonification of short (calcaneus), long (ulna, radius, tibia) and flat (ilium) bones with prevalence of trabecular, compact or combined types of bone structure. The multi-site approach has demonstrated a powerful diagnostic potential in preliminary clinical trials. The main objectives of Phase l are: (1) to develop an early prototype into a device ready for clinical testing by adding new algorithms for attenuation measurement, constructively changing probes, increasing quality of measurements, and new tools for standardized positioning; (2) to demonstrate potential diagnostic value of the developed device. Continuation of this project in Phase Il and beyond will result in a functional ergonomic instrument for mass screening of bone quality in normal and pathology, related to age, sex, and skeletal site. PROPOSED COMMERCIAL APPLICATIONS: The compact multi site bone ultrasonometer will serve as a mass screening tool for the primary detection of osteoporosis. There are multiple advantages over currently existing quantitative ultrasonometers, including ease of operation, lower cost, and significantly lower size and weight at comparable sensitivity. The proposed device offers a novel, complex approach to assessment of the bone density. There is a tremendous market potential for such device with the primary care market continuously growing in response to the maturing awareness of osteoporosis.